Respirators are commonly worn over the breathing passages of a person for at least one of two common purposes: (1) to prevent impurities or contaminants from entering the wearer's breathing track; and (2) to protect other persons or things from being exposed to pathogens and other contaminants exhaled by the wearer. In the first situation, the respirator is worn in an environment where the air contains particles that are harmful to the wearer, for example, in an auto body shop. In the second situation, the respirator is worn in an environment where there is risk of contamination to other persons or things, for example, in an operating room or clean room.
A variety of respirators have been designed to meet either (or both) of these purposes. Some of these respirators have been categorized as being “filtering face-pieces” because the mask body itself functions as the filtering mechanism. Unlike respirators that use rubber or elastomeric mask bodies in conjunction with attachable filter cartridges (see, e.g., U.S. Pat. RE39,493 to Yuschak et al.) or insert-molded filter elements (see, e.g., U.S. Pat. No. 4,790,306 to Braun), filtering face-piece respirators have the filter media cover much of the whole mask body so that there is no need for installing or replacing a filter cartridge. Conventional filtering face piece respirators have regularly comprised non-woven webs of thermally-bonding fibers or open-work plastic meshes to furnish the mask body with its cup-shaped configuration. As such, filtering face-piece respirators are relatively light in weight and easy to use. Examples of patents that disclose filtering face-piece respirators include U.S. Pat. No. 7,131,442 to Kronzer et al, U.S. Pat. Nos. 6,923,182 and 6,041,782 to Angadjivand et al. U.S. Pat. Nos. 6,568,392 and 6,484,722 to Bostock et al., U.S. Pat. No. 6,394,090 to Chen, U.S. Pat. No. 4,873,972 to Magidson et al., U.S. Pat. No. 4,850,347 to Skov, U.S. Pat. No. 4,807,619 to Dyrud et al., U.S. Pat. No. 4,536,440 to Berg, and Des. 285,374 to Huber et al.
Often a nose clip is provided on the mask body of the filtering face-piece to achieve a snug fit over the wearer's nose. The nose clip is commonly in the form of malleable, linear, strip of aluminum—see, for example, U.S. Pat. Nos. 5,307,796, 4,600,002, and 3,603,315 and U.K. Patent Application GB 2,103,491 A. A more recent nose clip product uses an M-shaped band of aluminum to improve fit over the wearer's nose—see U.S. Pat. No. 5,558,089 and Des. 412,573 to Castiglione. Other filtering face-piece respirators have used manually-pliable polymeric nose clips or spring-loaded nose clips—see U.S. Patent Applications 2007-0068529A1 to Kalatoor et al. and 2007-0044803A1 to Xue et al. Metal nose clips are regularly secured to the mask body through use of an adhesive, although welding techniques also have been suggested for polymeric nose clips.